This invention relates generally to cable trays or cable ladders and more particularly to such cable supporting apparatus having sheet metal rungs beat into a square tubular configuration and side rails of sheet metal roll-formed to have an inwardly projecting hollow flange therealong which is slotted thereacross at intervals to provide substantially square portions of flange around which the rung ends fit and are secured by means of wedging means.
Many trays for supporting electrical cables in an elevated position are known which can be assembled from component parts chosen to form tray sections of selected width, heights and length but such apparatus require costly manufacturing processes such as welding or special tools for erection at the assembly site. Many such trays have cable-contacting parts having sharp edges, such as when expanded metal or other perforate parts are used, or have fastening means for securing the parts together, such as bolts or screws, which have irregular surfaces capable of coming in contact with the supported cables and injuring their insulation.